1. Field of the Invention
The present invention relates to a system and method for performing minimally invasive cardiac procedures. More particularly, the present invention relates to a robotic system and surgical instruments that may be removably attached thereto, wherein said system aids in performing minimally invasive surgical procedures.
2. Description of Related Art
Blockage of a coronary artery may deprive the heart of the blood and oxygen required to sustain life. The blockage may be removed with medication or by an angioplasty. For severe blockage a coronary artery bypass graft (CABG) is performed to bypass the blocked area of the artery. CABG procedures are typically performed by splitting the sternum and pulling open the chest cavity to provide access to the heart. An incision is made in the artery adjacent to the blocked area. The internal mammary artery (IMA) is then severed and attached to the artery at the point of incision. The IMA bypasses the blocked area of the artery to again provide a full flow of blood to the heart. Splitting the sternum and opening the chest cavity, commonly referred to as xe2x80x98open surgeryxe2x80x99, can create a tremendous trauma on the patient. Additionally, the cracked sternum prolongs the recovery period of the patient.
There have been attempts to perform CABG procedures without opening the chest cavity. Minimally invasive procedures are conducted by inserting surgical instruments and an endoscope through small incision in the skin of the patient. Manipulating such instruments can be awkward, particularly when suturing a graft to an artery. It has been found that a high level of dexterity is required to accurately control the instruments. Additionally, human hands typically have at least a minimal amount of tremor. The tremor further increases the difficulty of performing minimally invasive cardiac procedures.
To perform MIS, the surgeon uses special instruments. These instruments allow the surgeon to maneuver inside the patient. One type of instrument that is used in minimally invasive surgery is forceps, an instrument having a tip specifically configured to grasp objects, such as needles. Because forceps and other instruments designed for minimally invasive surgery are generally long and rigid, they fail to provide a surgeon the dexterity and precision necessary to effectively carry out many procedures in a minimally invasive fashion. For example, conventional MIS forceps are not well suited for manipulating a needle during a minimally invasive procedure, such as during endoscopy. Therefore, many MIS procedures that might be performed, have, as of yet, not been accomplished.
In essence, during open surgeries, the tips of the various instruments may be positioned with six degrees of freedom. However, by inserting an instrument through a small aperture, such as one made in a patient to effectuate a minimally invasive procedure, two degrees of freedom are lost. It is this loss of freedom of movement within the surgical site that has substantially limited the types of MIS procedures that are performed.
Dexterity is lacking in MIS because the instruments that are used fail to provide the additional degrees of freedom that are lost when the instrument is inserted into a patient. One problem associated with this lack of dexterity is the inability to suture when the instruments are in certain positions. As a result, surgeries that require a great deal of suturing within the surgical site are almost impossible to perform because the surgical instruments to enable much of this work are not available.
Another problem associated with MIS is the lack of precision within the surgical site. For procedures such as the MICABG (Minimally Invasive Coronary Artery Bypass Graft), extremely small sutures must be emplaced in various locations proximate the heart. As such, precise motion of the tool at the tip of a surgical instrument is necessary. Currently, with hand positioned instruments, the precision necessary for such suturing is lacking.
As such, what is needed in the art is a tool and class of surgical instruments that may be articulated within the patient such that a surgeon has additional degrees of freedom available to more dexterously and precisely position the tool at the tip of the instrument, as is needed.
Additionally, what is needed in the art is a method and mechanism that provides simple handle, instrument and tool changing capabilities so that various tools may be easily and readily replaced to enable faster procedures to thus minimize operating room costs to the patient and to lessen the amount of time a patient is under anesthesia.
It is to the solution of the aforementioned problems to which the present invention is directed.
The present invention is a system for performing minimally invasive surgical procedures, and more particularly, minimally invasive cardiac procedures. The system includes a pair or more of surgical instruments that are coupled to a pair or more of robotic arms. The system may include only a single surgical instrument and a single robotic arm as well and as is hereinbelow disclosed. The instruments have end effectors that can be manipulated to sever, grasp, cauterize, irradiate and suture tissue. Each robotic arm is coupled to a master handle by a controller. The robotic arms may be selectively connected to a specific master handle such that a surgeon may selectively control one or more of a plurality of robotic arms. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors and the surgical tools attached thereto. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. This helps in removing any tremor the surgeon might have in their hands. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The scale factor may be effectuated via a voice recognition system, control buttons or the like. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed or toggled by the surgeon. Alternatively, the movement can be activated via voice control in a manner similar to the scaling factor adjustment set out hereinbelow. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient""s skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft or heart valve surgery.
The present invention is additionally directed to a surgical instrument and method of control thereof which permits the surgeon to articulate the tip of the instrument, while retaining the function of the tool at the tip of the instrument. As such, the instrument tip may be articulated with two degrees of freedom, all the while the tool disposed at the tip may be used.
The robotic system generally comprises:
a robotic arm;
a coupler attached to the arm;
a surgical instrument that is held by the coupler;
a controller; and
wherein movement at the controller produces a proportional movement of the robotic arm and surgical instrument.
The present invention may include a surgical instrument that has an elongated rod. The elongated rod has a longitudinal axis and generally serves as the arm of the endoscopic instrument. An articulate portion is mounted to and extends beyond the elongated rod. Alternatively, the articulate portion may be integrally formed with the elongated rod. The articulate portion has a proximal portion, a pivot linkage and a distal portion. The proximal portion may include a pair of fingers. The fingers may be orthogonal to each other and oriented radially to the longitudinal axis of the elongated rod. For use in surgical procedures, it is generally preferable that the instrument and the majority of the components therein are formed of stainless steel, plastic, or some other easily steralizable material. Each of the fingers may have at least one aperture formed therein to allow the passage of a pin which aids in the attachment of the pivot linkage to the proximal portion of the articulate portion and which allows the pivot linkage to be pivotally mounted to the proximal portion. The articulate portion provides articulation at the tip of an instrument that includes the articulate portion. More particularly, this provides additional degrees of freedom for the tool at the tip of an instrument that includes an articulate portion.
An instrument such as that disclosed hereinbelow, when used in conjunction with the present surgical system, provides the surgeon additional dexterity, precision, and flexibility not yet achieved in minimally invasive surgical procedures. As such, operation times may be shortened and patient trauma greatly reduced.
To provide increased precision in positioning the articulated tip as disclosed hereinbelow, there is provided two additional degrees of freedom to the master controller. Each of the two additional degrees of freedom are mapped to each of the degrees of freedom at the instrument tip. This is accomplished through the addition of two joints on the master and automatic means for articulating the instrument tip in response to movements made at the master.